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810SA/811SA: Installation, Start–Up, Operating and Service and Maintenance Instructions
1. Heating
The wall thermostat "calls for heat," closing the R-to-W circuit.
The furnace control performs a self-check, verifies the pressure
switch contacts PRS are open, and starts the inducer motor IDM.
a. Inducer Prepurge Period – As the inducer motor IDM comes
up to speed, the pressure switch contacts PRS close, 24 VAC
power is supplied for a field installed humidifier at the HUM
terminal and the control begins a 15-sec prepurge period.
b. Igniter Warm-Up – At the end of the prepurge period, the
Hot-Surface igniter HSI is energized for a 17-second igniter
warm-up period.
c. Trial-for-Ignition Sequence – When the igniter warm-up period
is completed, the main gas valve relay contacts GVR close to
energize the gas valve GV, the gas valve opens, The gas valve
GV permits gas flow to the burners where it is ignited by the
HSI. Five seconds after the GVR closes, a 2-second flame
proving period begins. The HSI igniter will remain energized
until the flame is sensed or until the 2-second flame proving
period begins.
d. Flame-Proving – When the burner flame is proved at the
flame-proving sensor electrode FSE, the furnace control CPU
begins the blower-ON delay period and continues to hold the gas
valve GV open. If the burner flame is not proved within two
seconds, the control CPU will close the gas valve GV, and the
control CPU will repeat the ignition sequence for up to three
more Trials-For-Ignition before going to Ignition-Lockout.
Lockout will be reset automatically after three hours or by
momentarily interrupting 115 vac power to the furnace, or by
interrupting 24 vac power at SEC1 or SEC2 to the furnace
control CPU (not at W, G, R, etc.) If flame is proved when flame
should not be present, the furnace control CPU will lock out of
Gas-Heating mode and operate the inducer motor IDM until
flame is no longer proved.
e. Blower-On Delay – If the burner flame is proven, the blower
motor is energized on HEAT speed 25 sec after the gas valve GV
is energized.
Simultaneously, the electronic air cleaner terminal EAC-1 is
energized and remains energized as long as the blower motor
BLWM is energized.
f. Heat-Off Delay – When the thermostat is satisfied, the R-to-W
circuit is opened, de-energizing the gas valve GV, stopping gas
flow to the burners, and de-energizing the 24-v humidifier
terminal 24VAC HUM. The inducer motor IDM will remain
energized for a 5-second post-purge period. Then turn off the
inducer motor and HUM (115-v) humidifier terminal. The
blower motor BLWM and air cleaner terminal EAC 1 will remain
energized for 90, 120, 150, or 180 seconds (depending on the
HEAT-OFF delay selection). The furnace control CPU is
factory-set for a 120-second Heat-Off Delay.
g. Blower-Off Delay – When the thermostat is satisfied, the
R-to-W circuit is opened, de-energizing the gas valve GV,
stopping gas flow to the burners, and de-energizing the
humidifier terminal HUM. The inducer motor IDM will remain
energized for a 5-second post-purge period. The blower motor
BLWM and air cleaner terminal EAC-1 will remain energized for
90, 120, 150, or 180 seconds (depending on the blower-OFF
delay selection). The furnace control CPU is factory-set for a
120-second blower-OFF delay.
2. Cooling Mode
(See
Fig. 24
for thermostat connections.) The thermostat closes the
R-to-G-and-Y circuits. The R-to-Y circuit starts the outdoor unit,
and the R-to-G and Y circuits start the furnace blower motor
BLWM on COOL speed. The electronic air cleaner terminal EAC-1
is energized with 115 vac when the blower motor BLWM is
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
operating. When the thermostat is satisfied, the R-to-G-and-Y
circuits are opened. The outdoor unit will stop, and the furnace
blower motor BLWM will continue operating on the COOL speed
for an additional 90 sec. Cut jumper J2 to reduce the cooling
off-delay to 5 sec (see
3. Continuous Blower Mode
When the R-to-G circuit is closed by the thermostat, the blower
motor BLWM will operate on continuous-blower speed FAN.
Terminal EAC-1 is energized as long as the blower motor BLWM is
energized.
During a call for heat, the blower BLWM will stop during igniter
warm-up (17 sec), ignition, and blower-ON delay (25 sec), allowing
the furnace heat exchangers to heat up more quickly, then restarts at
the end of the blower-ON delay period at HEAT speed.
When the thermostat "calls for cooling", the blower motor BLWM
will operate at COOL speed. When the thermostat is satisfied, the
blower motor BLWM will operate an additional 90 sec, on COOL
speed before reverting back to continuous blower speed.
When the R-to-G circuit is opened, the blower motor BLWM will
continue operating for an additional 5 sec, if no other function
requires blower motor BLWM operation.
4. Heat Pump
When installed with a heat pump, the furnace control automatically
changes the timing sequence to avoid long blower off times during
demand
defrost
cycles.
R-to-W-and-Y-and-G circuits are energized the furnace control
CPU will continue to turn on the blower motor BLWM at HEAT
speed, and begin a heating cycle. The blower motor BLWM will
remain on until the end of the prepurge period, then shut off for 24
sec then come back on at HEAT speed. When the W input signal
disappears, the furnace control begins a normal inducer post-purge
period and the blower switches to COOL speed after a 3 sec delay.
If the R-to-W-and-Y-and-G signals disappear at the same time, the
blower motor BLWM will remain on for the selected blower- OFF
delay period. If the R-to-W-and-Y signals disappear, leaving the G
signal, the blower motor BLWM will continue running the blower
motor at HEAT speed after the selected blower-OFF delay period is
completed.
Wiring Diagram
Fig. 50
shows a schematic for the furnace wiring diagram.
Troubleshooting
Refer to the service label (see
Fig.
51) can be a useful tool in isolating furnace operation problems.
Beginning with the word "Start," answer each question and follow the
appropriate arrow to the next item. The Guide will help to identify the
problem or failed component. After replacing any component, verify
correct operation sequence.
35
Fig.
28).
When
the
R-to-W-and-Y
Fig.
44). The Troubleshooting Guide (see
or
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